The present invention relates to the superficial treatment of steel in order to increase its resistance against corrosion or to improve its properties concerning frictional effects.
It has been proposed to coat a steel article with an organic varnish containing an appropriate powdered additional metal, such as tin or aluminium, and then to heat the surface to destroy the varnish and to cause the powder particles to migrate into the steel where they realize a layer of complex compounds which protects the underlying metal against corrosion. But these methods have not given very satisfactory results. Moreover the steel parts thus treated afford quite poor frictional properties.